[HTML5] Run Audio process in thread when available

This should fix some of the audio stuttering issues when the HTML5
export is compiled with threads support.
The API should be ported to AudioWorklet to (hopefully) be perfect.
That though, cannot be backported to 3.2 due to extra restriction of
AudioWorklet (which only runs in SecureContext, and needs a polyfill for
Safari).

1 files changed, 173 insertions, 0 deletions

diff --git a/platform/javascript/native/library_godot_audio.js b/platform/javascript/native/library_godot_audio.js
new file mode 100644
index 0000000000..d300280ccd
--- /dev/null
+++ b/platform/javascript/native/library_godot_audio.js
@@ -0,0 +1,173 @@
+/*************************************************************************/
+/*  library_godot_audio.js                                               */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+var GodotAudio = {
+
+	$GodotAudio: {
+
+		ctx: null,
+		input: null,
+		script: null,
+	},
+
+	godot_audio_is_available__proxy: 'sync',
+	godot_audio_is_available: function () {
+		if (!(window.AudioContext || window.webkitAudioContext)) {
+			return 0;
+		}
+		return 1;
+	},
+
+	godot_audio_init: function(mix_rate, latency) {
+		GodotAudio.ctx = new (window.AudioContext || window.webkitAudioContext)({
+			sampleRate: mix_rate,
+			latencyHint: latency
+		});
+		return GodotAudio.ctx.destination.channelCount;
+	},
+
+	godot_audio_create_processor: function(buffer_length, channel_count) {
+		GodotAudio.script = GodotAudio.ctx.createScriptProcessor(buffer_length, 2, channel_count);
+		GodotAudio.script.connect(GodotAudio.ctx.destination);
+		return GodotAudio.script.bufferSize;
+	},
+
+	godot_audio_start: function(buffer_ptr) {
+		var audioDriverProcessStart = cwrap('audio_driver_process_start');
+		var audioDriverProcessEnd = cwrap('audio_driver_process_end');
+		var audioDriverProcessCapture = cwrap('audio_driver_process_capture', null, ['number']);
+		GodotAudio.script.onaudioprocess = function(audioProcessingEvent) {
+			audioDriverProcessStart();
+
+			var input = audioProcessingEvent.inputBuffer;
+			var output = audioProcessingEvent.outputBuffer;
+			var internalBuffer = HEAPF32.subarray(
+					buffer_ptr / HEAPF32.BYTES_PER_ELEMENT,
+					buffer_ptr / HEAPF32.BYTES_PER_ELEMENT + output.length * output.numberOfChannels);
+			for (var channel = 0; channel < output.numberOfChannels; channel++) {
+				var outputData = output.getChannelData(channel);
+				// Loop through samples.
+				for (var sample = 0; sample < outputData.length; sample++) {
+					outputData[sample] = internalBuffer[sample * output.numberOfChannels + channel];
+				}
+			}
+
+			if (GodotAudio.input) {
+				var inputDataL = input.getChannelData(0);
+				var inputDataR = input.getChannelData(1);
+				for (var i = 0; i < inputDataL.length; i++) {
+					audioDriverProcessCapture(inputDataL[i]);
+					audioDriverProcessCapture(inputDataR[i]);
+				}
+			}
+			audioDriverProcessEnd();
+		};
+	},
+
+	godot_audio_resume: function() {
+		if (GodotAudio.ctx && GodotAudio.ctx.state != 'running') {
+			GodotAudio.ctx.resume();
+		}
+	},
+
+	godot_audio_finish_async: function() {
+		Module.async_finish.push(new Promise(function(accept, reject) {
+			if (!GodotAudio.ctx) {
+				setTimeout(accept, 0);
+			} else {
+				if (GodotAudio.script) {
+					GodotAudio.script.disconnect();
+					GodotAudio.script = null;
+				}
+				if (GodotAudio.input) {
+					GodotAudio.input.disconnect();
+					GodotAudio.input = null;
+				}
+				GodotAudio.ctx.close().then(function() {
+					accept();
+				}).catch(function(e) {
+					accept();
+				});
+				GodotAudio.ctx = null;
+			}
+		}));
+	},
+
+	godot_audio_get_latency__proxy: 'sync',
+	godot_audio_get_latency: function() {
+		var latency = 0;
+		if (GodotAudio.ctx) {
+			if (GodotAudio.ctx.baseLatency) {
+				latency += GodotAudio.ctx.baseLatency;
+			}
+			if (GodotAudio.ctx.outputLatency) {
+				latency += GodotAudio.ctx.outputLatency;
+			}
+		}
+		return latency;
+	},
+
+	godot_audio_capture_start__proxy: 'sync',
+	godot_audio_capture_start: function() {
+		if (GodotAudio.input) {
+			return; // Already started.
+		}
+		function gotMediaInput(stream) {
+			GodotAudio.input = GodotAudio.ctx.createMediaStreamSource(stream);
+			GodotAudio.input.connect(GodotAudio.script);
+		}
+
+		function gotMediaInputError(e) {
+			out(e);
+		}
+
+		if (navigator.mediaDevices.getUserMedia) {
+			navigator.mediaDevices.getUserMedia({"audio": true}).then(gotMediaInput, gotMediaInputError);
+		} else {
+			if (!navigator.getUserMedia)
+				navigator.getUserMedia = navigator.webkitGetUserMedia || navigator.mozGetUserMedia;
+			navigator.getUserMedia({"audio": true}, gotMediaInput, gotMediaInputError);
+		}
+	},
+
+	godot_audio_capture_stop__proxy: 'sync',
+	godot_audio_capture_stop: function() {
+		if (GodotAudio.input) {
+			const tracks = GodotAudio.input.mediaStream.getTracks();
+			for (var i = 0; i < tracks.length; i++) {
+				tracks[i].stop();
+			}
+			GodotAudio.input.disconnect();
+			GodotAudio.input = null;
+		}
+	},
+};
+
+autoAddDeps(GodotAudio, "$GodotAudio");
+mergeInto(LibraryManager.library, GodotAudio);